1. Field of the Invention
The present invention relates to fluid dispensing apparatus and, more particularly, to a robust, relatively simple, low-cost, and easily actuatable dispensing valve for dispensing fluid from a source of such fluid, which valve may withstand sterilization procedures including irradiation up to 5.0 MRAD and high temperature steam and chemical sterilization processes without degradation of the integrity of the valve structure or operation, and thus may be used for dispensing a wide variety of products ranging from aseptic products (free from microorganisms), to sterile products, to non-sterile products.
2. Description of the Background
Dispensing valves for dispensing fluid from fluid containers, systems, or other sources of such fluid are shown by U.S. Pat. Nos. 3,187,965; 3,263,875; 3,493,146; 3,620,425; 4,440,316; 4,687,123; and 5,918,779. Such valves can be used, for example, in a system for dispensing beverages or other liquids used by consumers in the home. Low cost, trouble-free, and reliable valve action are significant considerations in these applications. Low cost is particularly important if the valve is to be sold as a disposable item as, for example, where the valve is provided with a filled fluid container and discarded along with the container when the fluid has been consumed.
In U.S. Pat. No. 3,187,965, a dispensing valve for a milk container is shown having a generally integral valve body connected at one end to the milk container. The valve body has an L-shaped passage formed therein defining an inlet opening at one end in communication with the milk container and at the opposite end a discharge outlet for discharging the milk to the exterior of the container. A plunger bore in the valve body provides means for slidably mounting a plunger member. A valve seal fixedly connected to the inner end of the plunger member can be moved by the plunger member to open and close the inlet opening. The opposite or outer end of the plunger member extends to the exterior of the milk container. A push button having a diameter substantially larger than the plunger member is mounted to the outer end of the plunger member and disposed in the valve body so that the push button is exposed for engagement by a user""s finger. A compression type spring is engaged between the push button and the valve body. Thus, when a force is exerted against the push button to move the valve seal and open the inlet opening for dispensing milk from the container, the spring at all time exerts a substantial counter force on the push button for returning the valve seal to a closed position. The force exerted by the compression spring tends to increase directly with the inward displacement of the plunger member. Therefore, the user must exert considerable inward force on the push button to hold the valve open.
Another valve, shown in U.S. Pat. No. 3,263,875, uses a similar plunger member and valve body to that of the ""965 patent. A resilient diaphragm having a peripheral portion engaged with the valve body acts both as a return spring and as a push button. Unfortunately, commercially-available valves having such diaphragmatic actuator members have in the past required the user to exert considerable force to hold the valve open while dispensing the liquid.
Likewise, commercial attempts have been made to provide low-cost dispensing valves for use with disposable containers, but such efforts have met with limited success. For example, Waddington and Duval Ltd. provide a press tap for use with disposable containers (such as wine boxes, water bottles, and liquid laundry detergent containers) under model designations COM 4452 and COM 4458, both of which provide a depressible button actuator operatively connected to a valve closure for moving the valve closure away from a valve seat to dispense fluid. Unfortunately, the valve constructions are configured such that fluid to be dispensed will rest within the dispensing chamber of the valve behind the valve seat after use and thereby outside of any refrigerated or insulated container in which the liquid is stored, thus increasing the risk of spoilage of the volume of fluid resting within the valve body after each use. Moreover, many fluid dispensing applications require vigorous sterilization procedures prior to use of the dispensing equipment, including irradiation at exposures of up to as high as 5.0 MRAD, and high temperature steam and chemical sterilization procedures. The thin-walled polyethylene construction of the valve bodies of the Waddington and Duval dispensing valves cannot withstand such sterilization procedures, and in fact become brittle and prone to failure when exposed to such procedures, thus greatly limiting their use for dispensing food products. Even further, the polyethylene valve closure of the Waddington and Duval dispensing valve construction is highly thermally conductive, such that heat transfer may easily occur between the exterior of the fluid container and the contents of the container simply through the valve structure, again raising the risk of spoilage of the contents.
Similarly, the Jefferson Smurfit Group provides a similar tap for use with disposable containers under the model designation VITOP. Once again, the Jefferson Smurfit Group tap construction is configured such that fluid to be dispensed will rest within the dispensing chamber of the valve behind the valve seat after use and thereby outside of any refrigerated or insulated container in which the liquid is stored, once again increasing the risk of spoilage of the volume of fluid resting within the valve body after each use. Likewise, the thin-walled polypropylene construction of the valve body of the Jefferson Smurfit Group dispensing valve cannot withstand the above-described sterilization procedures, and also becomes brittle and prone to failure when exposed to such procedures, thus greatly limiting their use for dispensing food products. And, as above, the polyester elastomer closure of the Jefferson Smurfit Group dispensing valve construction is highly thermally conductive, such that heat transfer may easily occur between the exterior of the fluid container and the contents of the container simply through the valve structure, again raising the risk of spoilage of the contents.
Thus, although substantial effort has been devoted in the art heretofore towards development of low-cost valves of this general type, there remains an unmet need for a valve which is easier to use and which does not require that the user exert such large forces to hold the valve open. This problem is complicated by the fact that the spring or other resilient member should provide the force necessary to assure leak-free seating of the valve seal when the plunger member is in the closed position. Likewise, there remains an unmet need for a disposable valve which is sufficiently robust so as to be able to withstand vigorous sterilization procedures, which reduces heat transfer through the valve between the interior and exterior of the fluid container, and which does not trap fluid outside of the intended storage vessel between dispensing cycles.
Moreover, for a dispensing valve provided as a component of a throw-away fluid container, it would be highly advantageous to provide an easy to use dispensing valve which offers the user assurance that the valve has not previously been used or tampered with, and that the integrity of the contents of the fluid container has not been compromised. Unfortunately, the need for such a feature has not been met by prior art dispensing valves.
There is further need for a valve which can be adapted, during manufacture, to provide the desired liquid flow rate for a particular set of conditions such as liquid viscosity and the liquid pressure or xe2x80x9cheadxe2x80x9d available to force the liquid through the valve body. A valve which discharges a thick, high-viscosity fluid such as cold maple syrup or orange juice concentrate at a desirable rate will discharge a low-viscosity fluid such as water or wine under the same pressure at a far higher rate. It would be desirable to provide a valve which can be fabricated readily using normal production techniques such as injection molding in a range of configurations, having different resistance to fluid flow, to provide for these different conditions. It would be particularly desirable to provide a valve which can be fabricated in these different configurations while with only minor modifications to the molds and other tools used to make the valve.
It is, therefore, an object of the present invention to provide a fluid dispensing valve which avoids the disadvantages of the prior art.
It is another object of the present invention to provide a fluid dispensing valve which requires minimal force to maintain the valve in an open position while providing leak-free closure of the valve when seated in a closed position.
It is yet another object of the present invention to provide a fluid dispensing valve which may be manufactured in a variety of configurations to allow effective application to fluids of varying viscosities with only minor modifications to manufacturing equipment used to make the valve.
It is even yet another object of the instant invention to provide a fluid dispensing valve which provides a user a means of determining whether or not the valve has previously been actuated and possibly compromised the integrity of the fluid to be dispensed.
It is still even yet another object of the instant invention to provide a fluid dispensing valve which is of sufficiently robust construction so as to withstand sterilization procedures including exposure to high levels of radiation and high temperature steam and chemical sterilization without degrading the performance or integrity of the valve structure.
It is still yet another object of the instant invention to provide a fluid dispensing valve which reduces heat transfer from the exterior of a liquid container to which the valve is attached to the interior of the container.
It is still even yet another object of the instant invention to provide a fluid dispensing valve which prevents the storage of fluid behind the valve closure and outside of the fluid container after each dispensing cycle.
In accordance with the above objects, a dispensing valve for fluids is disclosed which provides for ease of use by requiring only a minimal force exerted on the valve actuator to maintain the valve in an open position, and which offers a simple, ergonomic design and robust functionality capable of dispensing a wide variety of products. In a first embodiment, the valve body and actuator are formed of a polypropylene copolymer with an average wall thickness of approximately 0.0625 inches, and the valve seal is formed of a thermoplastic rubber having an average thickness of about 0.032 inches. Such dimensional characteristics and materials allow the dispensing valve to withstand the highest aseptic sterilization regimentation as outlined by the Food and Drug Administration (FDA) and maintain the sterility of a product as specified by the National Sanitation Foundation (NSF) guidelines. More specifically, the dispensing apparatus is able to withstand either gamma or cobalt irradiation at the maximum dose of 5.0 MRAD (50 Kilogray) in the first phase of the sterilization process. The dispensing apparatus is then able to withstand the high temperatures associated with the steam and chemical sterilization processes required in the filling process. The dispensing apparatus is capable of withstanding these combined sterilization regimens without degrading the valve structure or operation. Thus, the valve of the instant invention may be used to dispense products ranging from aseptic products (free from microorganisms) including but not limited to dairy, 100% juice and soy products, to commercially sterile products including but not limited to preserved juice and coffee products, to non-sterile fluids such as chemical solvents.
In order to allow a minimal force for holding the valve in an open position, a resilient valve actuator having the characteristics of a nonlinear spring is provided at an actuator end of the valve body and operatively connected to a plunger, with the opposite end of the plunger having mounted thereon a resilient valve seal. An intermediate discharge outlet is positioned between the actuator end and the valve seal, such discharge outlet being placed in fluid communication with the interior of a fluid container to which the valve is attached when the valve is in an open position. A valve port wall is positioned between the valve seal and the dispensing chamber providing a plurality of ports for controlling the flow of fluid through the valve body when the valve is in an open position. The valve and the valve port wall are positioned such that when the valve is installed on a liquid container, virtually no liquid will be trapped by the valve structure outside of the insulated container, thus preventing the spoilage of a dose of liquid resting in the valve after each dispensing cycle. A push-button is provided for actuating the dispensing valve and is exposed to the exterior of a fluid container to which the dispensing valve is attached. In one embodiment of the instant invention, the push-button is concentrically mounted within a breakaway circular rim. Upon first using the dispensing valve, a user depresses the push-button, dislodging the circular rim from the button, and thereby providing evidence that the valve had been opened, thus providing a tamper-evident actuator. The valve may be manufactured with a variety of port configurations to provide for the dispensing of fluids of varying viscosities.
The simplicity and functionality of the dispensing valve of the instant invention enables its manufacture and automatic assembly with high cavity tools which in turn reduces manufacturing costs and offers the market a low cost dispensing solution. The simplicity and functionality of the design also enables the dispensing apparatus to be easily customized in the manufacturing process to fit a wide range of dispensing packages such as a flexible pouch, flexible bag, or semi-rigid plastic container. The dispensing valve of the instant invention is also configured to easily adapt to a wide range of filling machines and filling conditions worldwide.